教員紹介

流域環境学プログラム

フィールド科学人材育成プログラム

ウィタカ アンドリュー

准教授

担当講義：流域水文学、技術コミュニケーション入門、測量学実習

グリーティング

研究分野・テーマ

研究業績・略歴

アルバム

リンク

グリーティング

I’m a field hydrologist, interested in the role of snow in the hydrological cycle, and how this is changing with ongoing climate change and global warming. Niigata and most of northern Japan currently depend on abundant snowmelt during the spring season for rice paddy irrigation, but how much snowmelt will there be in a warmer climate? This is one of the important questions that I address in my teaching and research.

研究分野・テーマ

My main field of research is catchment hydrology, especially concerning snowmelt, sediment transport, and the hydrological regime of river basins. I strive to study the actual processes through long-term fieldwork, and since 2000 I’ve been monitoring streamflow and snowpack processes at the Takiya River catchment in northern Niigata Prefecture in connection with these three themes:

1. Influence of climate change on the hydrological regime in headwater basins
Global warming will lead to winters with less snow and more rain in maritime areas such as Niigata. Climate change scenarios published by IPCC show a likely winter warming of 2-3°C by 2100, which means a much smaller spring snowpack and much less snowmelt during the irrigation season. I’m using hydrological and snowmelt modelling techniques to assess the likely changes in the seasonal flows of rivers due to climate change.

2. Estimation of snowpack water and energy balance under forest canopies
Forest canopies strongly control the water and energy balance of the snowpack, which in turn determines the amount and rate of snowmelt, and streamflow. We also manage the forest in ways that change dramatically the nature of the forest canopy. What happens to snow caught in the forest canopy, and how is the water and energy balance different between species? These are some of the questions I’m researching through fieldwork in northern Niigata Prefecture.

3. Suspended sediment and bed load dynamics in gravel bed streams
Rivers carry not only water but also much sediment during times of heavy rainfall or snowmelt. Suspended sediment and bed load are deposited downstream on river flood plains or behind dams. Monitoring sediment processes in the Takiya River, we have tracked changes of great magnitude after the occurrence of extreme summer floods. I’m interested in how extreme rainfall and flooding triggers changes in sediment supply dynamics, leading to channel change and instability.